Error in EV Policy in Apigee X

[Anupam2]

I am getting the following error:-

{
    "fault": {
        "faultstring": "Failed to execute the ExtractVariables: Extract-Variables-1",
        "detail": {
            "errorcode": "steps.extractvariables.ExecutionFailed"
        }
    }
}

I want to fetch the json data from The Url using Service Call Out in the Extract Variable Policy.
So, the response from URL(https://35.244.239.45.nip.io/authdummy) should be stored in response variable using 
<Response>response</Response>. But whenever i am putting Source as response in EV Policy it is throwing Fault Error. It is always accepting Source as Request. Not sure Why?.

Service Callout Code:-

<ServiceCallout continueOnError="false" enabled="true" name="Service-Callout-1">
  <DisplayName>Service Callout-1</DisplayName>
  <Properties/>
  <Request variable="myRequest">
    <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
    <Set>
      <Headers>
        <Header name="username">abc</Header>
        <Header name="password">1234</Header>
      </Headers>
    </Set>
  </Request>
  <HTTPTargetConnection>
    <Properties/>
    <URL>https://35.244.239.45.nip.io/authdummy</URL>
  </HTTPTargetConnection>
  <Response>response</Response>
</ServiceCallout>

EVCode:-

<ExtractVariables continueOnError="false" enabled="true" name="Extract-Variables-1">
  <DisplayName>Extract Variables-1</DisplayName>
  <JSONPayload>
    <Variable name="result">
      <JSONPath>$.message</JSONPath>
    </Variable>
  </JSONPayload>
  <Source>response</Source>
</ExtractVariables>

Proxy Endpoint:

<ProxyEndpoint name="default">
  <PreFlow name="PreFlow">
    <Request>
      <Step>
        <Name>Service-Callout-1</Name>
      </Step>
      <Step>
        <Name>Extract-Variables-1</Name>
      </Step>
      <Step>
        <Name>JavaScript-1</Name>
      </Step>
    </Request>
    <Response/>
  </PreFlow>
  <Flows/>
  <PostFlow name="PostFlow">
    <Request/>
    <Response/>
  </PostFlow>
  <HTTPProxyConnection>
    <BasePath>/demo1</BasePath>
  </HTTPProxyConnection>
  <RouteRule name="noroute"/>
</ProxyEndpoint>

Can any one please help?

[dchiesa1]

Yes, the first thing I would do, if I were you , is NOT use <Response>response</Response>. "response" is the name of the message that gets populated by Apigee automatically when Apigee sends a message to an upstream system via a TargetEndpoint . Think of it as a "reserved" variable.

Use ANYTHING other than that variable name in ServiceCallout.

<Response>myAuthResponse</Response>

And then modify your ExtractVariables to reference that variable

<ExtractVariables continueOnError="false" enabled="true" name="Extract-Variables-1">
  <DisplayName>Extract Variables-1</DisplayName>
  <JSONPayload>
    <Variable name="result">
      <JSONPath>$.message</JSONPath>
    </Variable>
  </JSONPayload>
  <Source>myAuthResponse</Source>
</ExtractVariables>